That’s the question mark hanging over one of the most intriguing horses in Saturday’s Preakness, Rock Hard Ten, who swooped out of the skies yesterday to throw down the gauntlet to the reigning star Smarty Jones.

Hard-headed realists wonder: why bother? Rock Hard Ten did not race as a 2-year-old, he has had only three lifetime starts (at Santa Anita), he has never won a stakes race, he hasn’t had a race in six weeks and he’s taking on six battle-hardened rivals from the Kentucky Derby.

He is being asked to climb a mountain. The assignment violates most of the traditional principles of thoroughbred racing.

Yet, when the gates spring open Saturday, Rock Hard Ten may be no more than 6-1, according to the local oddsmaker. The reason is that many believe him to be the sleeper of the season, a potentially good horse just waiting for the big showcase.

His connections initially flew him from Los Angeles to Louisville, hoping to run in the Kentucky Derby, but his meager earnings shut him out. They immediately pointed him for the Preakness.

And as if to underline the seriousness of the horse’s mission, topline American jockey Gary Stevens is flying from France to ride him. Stevens recently moved to Paris to ride under contract to top trainer Andre Fabre. He’s not in the habit of chasing moonbeams, so his intent is a powerful signal of his opinion of Rock Hard Ten.

The colt set hearts aflutter in his very first race, a seven-furlong maiden special in early February. With Stevens aboard, he won in a breeze in the stunning time of 1:22.1, good enough to earn him a huge Beyer speed figure of 101.

But the word had not reached railbirds. He started at better than 6-1. Not next time. A month later, in his second outing, a mile allowance, he bombed the field at 3-5 under Stevens.

His young Canadian-born trainer Jason Orman then did an amazing thing: pitch-forked him straight into the Santa Anita Derby, where he was bet down to 3-1 and nearly won it all.

Rock Hard Ten, with David Flores sitting in for Stevens, swept round the field on the turn, hit the front inside the furlong pole, then shifted course slightly under pressure. He was beaten a head by Castledale, then disqualified to third for interfering with Imperialism (whom he will meet again in the Preakness).

Rock Hard Ten has since had five hard drills at Churchill Downs, including a couple of bullet works.

“I would have liked him to have a couple more starts under his belt,” Orman said yesterday, “but he’s doing so well that I think he can compete with these horses and he deserves the chance.”

Orman does not underestimate the magnitude of the challenge.

“Smarty Jones and Lion Heart are very good horses,” he said. “But hopefully our horse is good enough to beat them and win.”

No lack of confidence there.

Orman writes off the Santa Anita Derby disqualification as evidence that Rock Hard Ten was “a bit green” since he had only had two starts. “He learned a lot from that experience,” the trainer said.

Rock Hard Ten, a son of the late-staying sire Kris S., has 10 Preakness winners in his bloodlines. He is owned by Mercedes Stable, operated by Ernie Moody, a Las Vegas video poker gaming investor, and Madeleine Paulson (the widow of Allen Paulson) who also bred him.

Paulson also bred Azeri, Horse of the Year for 2002.

Orman, 35, hails from Calgary, but has had wide experience with thoroughbreds, including stints in Saudi Arabia and Singapore. Would you believe – he was once an assistant to a trainer named Marty Jones. Not Smarty Jones, Marty Jones.

Yesterday, he answered the question – again – of what he’s doing at the Preakness with Rock Hard Ten. “This,” he said, “is a very good horse, and I definitely think he can compete with these horses. He still has a lot of room to improve.”